Circuit breaker



CIRCUIT BREAKER Filed July 25, 1941 2 Sheets-Sheet l 3'11 12 John Gui?i332 Feb. 23, 1943' J. G. JACKSON CIRCUIT BREAKER Filed July 25, 1941 2Sheets-Sheet 2 INVENTOR (/0717? 6: Jackson ATTO. NEY

Patented Feb. 23, 1943 CIRCUIT BREAKER John G. Jackson, Detroit, Michassignor to Square B Company, Detroit, Mich, a corporation of MichiganApplication July 25, 1941, Serial No. 403,936

'7 Claims.

This invention relates to automatic electric circuit breakers and moreparticularly to the current responsive tripping means for eilectlng theautomatic opening of such circuit breakers upon and 8 within an arcingchamber. an operating handle is provided at H pivotally mounted upon ashaft 12 and having a cam surface eooperat-= ing with the fiat surfaceor" the member to effect current overload. manual movement or thecontact has "i. A com One object of the present invention is topropression spring i i is disposed between the botvide a simple andeconomical but effective comtom of the base i and the bar l to bias thebined thermal and magnetic tripping means for same. an automaticelectric circuit breaker. The lower end of the base is rovided with anAnother object of this invention is to provide end lacing terminalcomprising a conducting tripping means for an automatic electric circuitconnector i5 inserted in slots in the opposite side breaker including ayoke and a movable armawalls of the base from the front and maintainedture member with an intermediate member caragainst endwise removal byboth a terminal rying a latching surface moved by the armature screw i6and an adjusting stud ll. A midwee to eilect tripping of the circuitbreaker. 15 tion of the connector is pressed outwardly at it Anotherobject of the invention is to provide a to take up any slack or play theconnector combined thermal magnetic tripping means for a mounting. A tab5!; is pressed out of the con circuit breaker according to the precedingobject nector and the stud l'l is threaded into the in which abimetallic member is provided for also i9 to provide for adjustment ofthe free end oi 'eflecting movement of the intermediate member abimetallic member welded on the end of carrying the latching surface.connector, thus providing for adjustment of Other objects and featuresof the invention calibration oi the breaker the hi will be readilyapparent to those skilled in the metallic element 2! is a magnetic yoke22 which art from the specification and appended drawings is 01'generally U-shape provided with side pins illustrating certain preferredembodiments in 25 23 received within slots on opposite side walls ofwhich: the base to mount the yoke. A magnetic arma- Figure l is avertical sectional view 0! a-iorm oi ture element 24 is provided havinga central slot circuit breaker including the current responsive 25through which the contact bar passes in its tripping means of thepresent invention. automatic tripping and resetting movements. Figure 2is a detail plan view of the tripping An intermediate non-magneticelement 25 is promeans according to the present invention shown vicledbetween the sides of the yoke. This elewith the circuit breaker coverremoved. ment has return bent tabs at its front end at 21' Figure 3 is adetail sectional view on the line and the loops thus formed bear againstthe inside III-III 0! Figure 1. surface of an insulatmg fiber plate 28which, Figure 4 is a detail sectional'view on the line with the metalplate 29, is sealably attached to IV-IV of Figure 1. the breaker to forma cover therefor. The mem- Figure 5 is a partial vertical sectional viewber 26 rotates about the engagement of the loop showing a slightlymodified form of the tripping 2'1 with the inner surface of the sheetit. means. The armature 21 has recessed rounded portions The presentinvention has been illustrated in 40 ll received within the loops 2'!which form bearconnection with a circuit breaker mechanism lugs for therotation of the armature, The upper which comprises a base I having aconducting end of the armature is provided with projecting strap Imounted on one end ledge thereof and tongues 32 received within notchesin the oppocarrying at its interior end a stationary contact site sidewalls of the base which serve to limit the 3, the connector 2 extendingthrough an opening movement of the assemblage. Mounted upon in a fiberplate 4 which closes the end of the. the non-magnetic intermediatemember 25 is a base. Exterior oi the plate 4 is a terminal conresilientspring strip 83 welded to the intermedinector 5 for attachment ofcircuit wiring. Guided ate member adjacent a midpoint and formed to forrectilinear movement within the base is a provide alatching tip at Hbiased by its resiliency generally U-shaped element 6 upon whose long soaway from the plane of the intermediate memleg is pivotally mounted, byinter-engaging bar, but whose position is limited by the engagenotches,a contact bar 1 carrying at one end a ment with the intermediate memberof the flange movable contact i cooperating with the station- 35 formedat the end of the leg 36. The oppoary contact 3. Fiber plates indicatedat 9 comsite end of the spring strip 33 is formed as shown bine with theplate 4 to enclose the contacts 3 to engage both the surface oi thefiber sheet 28 aid the armature a; isstatemt with as; iiber sheet 28 isindicated'at 11 and the enga e-1.

aerator mal flexing of the bimetali, the two exert a sumcient to eflecteventual release or the contact menttvith the armature is indicatedat98. By

its engagement with the iibersheet the resiliency oi the spring stripbiases the intermediate mem born in a counterclockwise direction asviewed in Figure 1. Similarly, the engagement of the resilient springstripwith the armature is at the point 33 biases the armature as well ina counterclockwise direction. The limiting position of the armature isdetermined by a stationary stop on thebas and the limiting position ofthe intermediate member 24 and hence the position oi the latching tip 34is determined by adjustment of.

the bimetal 2 l, the bimetal 2! being provided with the reduced tongue39 received within a slot 4|" in a right angle leg 42 provided at thefree end of the intermediate member 26. 1

The circuit breaker mechanism, as shown lni full lines in Figure 1-, isin its normally operating closed circuit position. The dotted linesOctober 19, 1937.

The operation of the tripping mechanism is asiollows:

For low current overloads of continued duration, the bimetal 2i becomesheated by the passage of current therethrough and flexes in a clockwisedirection to move the intermediate member and, accordingly, the latchingtip 34, to disengage the contact bar 1 which then rotates in a clockwisedirection into the dotted line position under the bias of the spring l0.Upon theoccurrence of heavier overloads, magmechanism in a shorterelapsed time than would be taken by the bimetal alone. When the fluxinduced in the magnetic circuit formed by the armature 2d and yoke 22becomes suflicient, the armature is rotated in a clockwise direction andstrikes the latching tip 35, moving it downwardly to release the bar '8as before. The movement oi the latching tip 3i may be efiected independ-26, or these two members may move together as a unit, depending uponwhether the bias of the spring strip 83 or the resistance of theintermediate member to movement is the greater. As a practical matter,the actual tripping movement of the latching tip is probably a combine.-tion of these movements. It is seen that with this arrangement themoving armature 24 strikes the latching tip 36 a her blow to overcomethe initial static friction opposing movement thereof.

While the operation of the tripping means for the breaker has beendescribed in terms of ther none elements of the tripping means operatequicker" than normal thermal flexing of the bimetal 29 to effect thetripping of the breaker 'ently of movement of the intermediate memberbar.

1 In the modified form of the invention illusstrip 83 is elongatedsumciently for the flange 85 to di rectly engage the lower, surface orthe bimetal ii i.

trated in Figure 5, the les .38 onthe TZF.

In this arrangement the leg 62 on the intermediate member 48 isomitt'ed'as is the tongue 89, on the bimetal. In this arrangementthe {asnetic operation is the same as previously d e' f scribed for thepreferred embodiment, but in the thermal tripping the iorceererted bythe bimetal' 2! is passed directly to the latching tip 34 through theleg l6 instead of operating on the intermea diate member 28. Again,whether the la tip 'is moved without moving the intermediate, member 28or the two are moved bodily together will depend upon the value of thebias of the" spring 33 and the resistance which the inte' diate memberoffers to rotation, the actual operation being immaterial which isproduced.

While this inventionhas been described in con nectlon with a particularcircuit breaker mocha? nism to show a complete operative structure, itis understood that the tripping means according; to the presentinvention is not limited to any pare ticular mechanism but may beutilized in many, other distinct mechanism forms to which it isadaptable and, while certain preferred embodi ments' of the inventionhave been specifically dis closed, it is understood that the inventionis not limited thereto, as many variations-will be roadie lyapparent tothose skilled in the art andv the prising a magnetic yolre, meansenergizing said yoke in responseto the flow of current through. thebreaker, an armature member movable to ward said yoke to efiect therelease of said re leasable means upon the passage of overload current,a non-magnetic intermediate membercarrying a latching surface engagingsaid re; leasable means and positionedin the path of said movablearmature so as to be moved thereby.

into a position where the releasable means. is released,

and said armature having rounded portions Ire ceived within the innerportions of the loop and rotating therein for. pivotal movement. 1

2. In an automatic electric circuit breaker an ing separable contactsand means releasable to eflect separation oi aaldcontacts, current 1 m..

sive means for effecting the release of said re? leasable means upon thepassage of an overload. current through the circuit breaker comprisinga" bimetallic member heated in response to the flow-. 0! current throughthe breaker, a magnetic yolre." means energizing. said yoke in responseto the flow oi current through the breaker, an a 701i. ture memberadapted to be attractedto said so) upon passage of an overload current,an aux-s iliary member carrying a latching surface en=" to the releasingreflect the terms of the toiletries.

circuit breaker" having separable contactsand means releasable to eflectseparation of said contacts, current re sponsive meansior eflecting therelease of said" releasable meansupou the passage of an over loadcurrent through. the circuitbreaker com said intermediate member havinglooped portions at one end with the outside oi. the loop bearing againsta fixed part to provide a bearing for rotation of the auxiliary memberdense to the M mm; on

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